Add DSAAuthentication to synced_folders/rsync & add PubkeyAuthentication

[mmlb]

This adds the DSAAuthentication=yes option to rsync's rsh command when appropriate, just like done in ssh. This should fix #8183.

I've also added support for PubkeyAuthentication as its been around for 20 years now and replaces DSAAuthentication. This is most beneficial when trying to debug ssh connection issues and searching for DSAAuthentication turns up very little information.

[hashicorp-cla]

All committers have signed the CLA.

[mmlb]

Not sure if adding PubkeyAuthentication to all ssh clients is ok or if I need to do something special for solaris or other oses. Also I'm expecting tests to fail atm, wanted to get this out first.

[mmlb]

ping @mitchellh @briancain @chrisroberts (according to git-blame&git-log)

[ashleemboyer]

Hi @mmlb! I've just merged in https://github.com/hashicorp/vagrant/pull/13048, which modified 120 MDX files and added a new workflow that would be good to have run on this PR. Since this is from a fork, I'm not sure I have permissions to rebase on main for you, so I wanted to send this quick message to let you know to update with main. Thanks!

[mmlb]

Hi @ashleemboyer I've rebased ontop of latest main and pushed, PTAL. I'd appreciate getting this over the wall and done!

[mmlb]

Also fyi @ashleemboyer it looks like those mdx link-checker checks are making assumptions that the PRs are always originating from this repo and not from forks. I've been notified that they failed on my fork/branch :( .

[mmlb]

I do not agree to license this change under the current vagrant license there for I am closing this PR.